You can search for data outside RIMMF from anywhere in RIMMF (while you are in a record, in a template, or at the main menu).
If the search 'timesout' (404 Request aborted on timeout) then it means the source server is busy, try again.
To view a MARC record before importing it:
If you decide to import a MARC record that you have found, into RIMMF:
One you have imported and added the converted record to your RIMMF database, you can edit it in RIMMF, and link to and from it, as usual.